Photosynthesis (1) WALT: Describe two experiments that demonstrate photosynthesis

Last lesson, we learnt….. Nitrates are needed for Nitrates are obtained from …………… by the …………….. Nitrates can pollute rivers …………….. Produce their own food through photosynthesis

LEAVES AND PHOTOSYNTHESIS

Leaves work in a similar way to the solar cell Leaves work in a similar way to the solar cell. They both need a lot of light energy to work. Photosynthesis takes place in the chloroplasts inside the leaf cells.

Chloroplasts contain chlorophyll, a green pigment that takes in energy from the sunlight. All green parts of plants are able to photosynthesis because they contain chlorophyll.

Can you remember the word equation again?

Word equation for photosynthesis carbon dioxide + water glucose + + light energy oxygen

released into atmosphere WATER from soil LIGHT from sun GLUCOSE for biomass and energy CHLOROPHYLL in the leaves CARBON DIOXIDE diffuses from the air OXYGEN released into atmosphere WATER from soil

The products of respiration are: Oxygen Glucose Oxygen – released as gas into the air. Some is re-used as respiration. Glucose – used for GROWTH (e.g. making cell walls or fruits) - or stored as STARCH

There are two experiments that always come up in Common Entrance There are two experiments that always come up in Common Entrance. We will look at one today. Turn to page 70. Take our leaves off the plant we semi-covered two days ago and carry out the experiment. What safety considerations do we have (hint: use of ethanol) Write down the steps you took in 5 points. Write down a conclusion of what it proved.

What did this experiment prove? Plants need light to photosynthesise So glucose is only produced in parts of the leaves which had sunlight on them This glucose was turned into starch

When you are finished… Continue with the questions from yesterday in the KS3 books.